Found this old post!
As JohnD1956 describes harmonic balancer can break if not installed correctly!
Exactly what has happened to my 322 -56!!
Motor seems to have been running for some time with loose balancer, all torn up inside. Crank seems not that beat up... Cross fingers it will work with a new balancer.
Can I just install a new balancer if crank is ok?
Or do I need to rebalance motor?